Potential-regulator for dynamo-electric machines.



V. G. APPLE.

POTENTIAL REGULATOR FOR DYNAMO ELECTRIC MACHINES.

APPLICATION FILED MAY 31, 1911.

1,100,340, Patented June 16, 1914.

i dam Wm m UNITED STATES PATENT OFFICE.

VINCENT G. APPLE, 0F DAYTON, OHIO, ASSIGNOB TO THE APPLE ELECTRIC.COMPANY, OF DAYTON, OHIO, A CORPORATION OF OHIO.

POTENTIAL-REGULATOR FOR DYNAMO-ELECTRIC MACHINES.

To all whom it may concern:

Be it known that I, VINCENT G. APPLE, a citizen of the United States,residing at Dayton, in the county of Montgomery and State of Ohio, haveinvented certain new and useful Improvements in Potential-Regulators forDynamo-Electric Machines, of which the following is a specification.

My invention relates to improvements in potential regulators for dynamoelectric machines.

One of the objects of my invention is to automatically maintain,substantially, constant the difference of potential, at the terminals ofa dynamo electric machine, and especially of machines of this class thatare driven by power-prodiibing motors, operating'at great variations ofspeed. I attain this object by causing magnetic variatip-ns in thedynamo electric machine as by setting up current undulations, directlyin the field magnetizing circuit of the machine after the speed. of thearmature thereof has reached, or exceeded, a predetermined velocity, andby varying the extent and frequency, and increasing the effectiveness ofsuch undulations, operatively proportional to the in creased velocity ofthe armature, beyond its predetermined critical speed, in conjunctionwith the reactive elfects, produced by tendency toward increased currentproduction circulating in the armature, upon the field magnets. ofsaiddynamo electric machine.

In the operation of my system, after the armature of the dyhamo hasreacheda predetermined speed, the magnetizing current, employed forenergizing the field .coils, is maintained suiliciently disturbed bypulsations, of greater or less frequency, or of varying time factors, asthe velocity of the armature increases beyond that predetermined degreeso as to set up the necessary reactions, the results of which are tomaintain the current in the working circuit substantially constantwithout material change of the electromotive-force, at the terminals ofthe arma- -ture, thereby to maintain it at substantially Specificationof Letters. Patent.

Application fil'ed May 31, 1911.

Patented June 16, 1914. Serial No. 630,419.

circuits shows, diagrammatically, the arrangement, construction andassociation of the parts necessary to carry my means of regulation intoeffect.

The dynamo-electric machine, with which I have shown my means ofregulation in the accompanying drawings, is of that type, known in theart, as shunt wound wherein the field is energized by an electric coilconnected across the terminals of the dynamo. If the current, in thefield magnetizing coil, of such a machine remains undisturbed, then theelectro-motive-force of the machine with unchanging load will be, tosome extent, proportional to the velocity of the armature. It is tomaintain a constant electro-motive force of the armature, after thespeed of the machine has reached a predetermined velocity that theresults of my invention are attained.

In association with, and as a part of my system, I employ a storagebattery, or accumulator, that is adapted to float upon the line afterthe electro-motive-force of the dynamo-electric machine has reached acertain'value, due to its speed. The battery is then cut into circuitwith the dynamo, and after the electro-motive-force of the dynamo hasfallen below the predetermined speed, at which the battery is to be cutinto the main circuit, the battery is automatically cut out or removedfrom the circuit with the dynamo but is still maintained in circuit withthe translating devices which are common both to the dynamo and to thebattery.

My system of regulation is especially desirable to be used in connectionwith lighting and ignition plants operated bythe motive engine of anautomobile, and in connection with train lighting wherein the drivingmotor, constituting the source of power, is adapted to be rotated atgreatly varying speed.

In installing the apparatus necessary to carry out my system ofregulation, I prefer to gear the dynamo-electric machine directly to theengine employed to drive the automobile at such ratio that theelectro-motiveforce desired to be maintained of cpns'tant value isreached at the time when the engine has arrived at a speed at which itis normally maintained during the greatest time'of its service, and whenthe engine is speded beyond this point, the regulating means, sooperates with respect to the dynamo eleci- 4, and 5, are connected tothe brushes, 2, and

3, respectively; To the wire 5, is connected a wire 6, between which,End the wire 7, a

storage battery 8, is included. The procontact screw 36, with which thearmature longation of the wire 7, constitutes one of the working mains9, between which and the main 10, the translating devices, that are tobe supplied with current, by the joint use of the dynamo-electricmachine and the storage battery, are connected.

11, and 12, are incandescent lamps, of which there may be any desirednumber, within the capacity of the current producers, and 13 is primaryof an induction coil; the secondary 14, of which, is connected to theterminals of the spark plug 15. The main, 10, is connected to wire 5, asat 16. An automatic switch, 17, is provided, with a coil, through whichthe working current produced by the dynamo passes. The coil 18, of saidswitch, is connected to the pivotal armature 19, as at 20. Between the.core 21, of the switch magnet, and the armature 19 is a retractilespring, 22, which non mally bears against the end of the magnet core andyieldingly holds the armature in c ntact with aback stop 23. i itchmagnet 17 is energized, it attracts its armature 19, which is adapted tomake electrical connection with the adjustable contact screw 24. Thelatter is connected, by wire 25, to the wire 7 as at 26. Several shunts,or subsidiary circuits I shall now trace. The shunt-field magnet-winding27 is connected to the main wire 4, as at 28, the other end; orterminal, of the field winding, being connected toa point 29. Theregulating magnet, consists of the usual magnetic device, comprisingyoke, 30, and the cores 31 and 32, having a responsive armature 33pivoted as. at 34. A block 35.,'is screw threaded, for the reception ofan adjustable 33, makes contact, when in retracted position. Anadjustable screw, 37, limits the forward movement of the armature. Are-' tractile spring 38, is connected to the armature 39, anditsstrength is adaptedto be adjusted by the screw 40. A resistance coil,41, is connected between the point 29 .and the wire 5, as at 42. Thecoil 41 is of much higher resistance, preferably, than the resistance ofthe field winding 27. In an example which has proven quite satisfactory,theresistance of coils 41 was ten times the resistance of the fieldwinding 27. A wire 43 connects the point 29 to the block 35, sup- Whenthe porting the contact screw 36, which makes contact with the retractedarmature 33. A coil 44, surrounds the core 32 of the regulating magnet,and is connected at one end to the wire 43, and at the other end to therheostat, or resistance 45, the latter having its other terminalconnected to wire 5 as at 46.

The resistance, 45, is relatively high. In the example,- which hasproved quite satisfactory to the applicant, this resistance wassomething near ten times greater than the resistance of the coil 41 andabout one hundred times greater than the resistance of the field magnetwindings. An adjustable rheostat, or resistance, 49,-is connected to oneof the main wires, 4, by wire, 50, as at 51. The contact 52, by means ofwhich any desired portion of the resistance, 49, may be included incircuit, is connected by wire 53 to a point 54. A coil, 55, surroundsthe core, .31, of the regulating. magnet, and is connected to point 54,the other end of coil 55 being connected by wire 56 to the main 5, as at57. Throughout the circuits, I have shown, by arrows, the direction ofthe current from the dynamo, and it will therefore be observed that thecoils 55 and 44 are opposed when energized. The automatic switch, orcutout, 17 is provided with a subsidiary reinforcing coil 58, oneterminal, of which, is connected to the terminal of the coil 18 as at59,the other terminal being connected to the wire 6, as at 60.

When the dynamo is set in operation, that is tosay, when its armature isrotated, by the proper means, the circuit will be completefthrough thefield magnet windings 27, as follows: starting at the point 28 from thewire 4, through the field magnet coil 27 to the point 29, thence overwire 43 to the block. 35, and through the armature 33 to the main wire5; thus completing the circuit through the field windings without theinclusion of any extraneous resistance. This will bevv the field windingcircuit at the time, previous to, or when the armature is being drivenat the normal speed at which it will generate the electro-motive-forcedesired to be maintained. Now, when the electro-motive-force rises,above normal value, as a result of increased speed of the dynamo, or

otherwise, current, sufiicient to operate the regulator, will then passfrom wire 4, over the wire 50, through the adjusted resistance 49,through the coil 55, and thence to the wire 5. It will be observed that,at the time, there is no material current pass? 11g through coil 44, dueto the short circuit, effected by the armature 33 and contact screw 36.When current, of sufficient value, has passed through the coil 55, dueto a slight excess in electro-m'otive-force, the armature, 33, will beattracted by the magnetism induced in the core 31-, by the coil 55, andthe contact will be broken between the armature 33 and the screw 36,thus permitting the current to pass from wire 43, through coil 44, andthrough the resistance 45, to the wire 5, at point 46. In the firstinstance, the armature 33, has been moved toward the core 31, againstthe retractile spring 38, after which, the coil 44, is thereby admittedinto the circuit, as just pointed out. Now it will be observed that thedirection of current, through coil 44, is'such, as to neutralize themagnetic efi'ect produced by coil 55, and therefore the retractilespring 38 is suflicient to draw the armature 33 again into contact withthe screw 36,thus cutting out the coil 44 and also shortcircuitingresistance coil41, at the same time, thus again increasing the currentthrough the field magnet coiL 27. Coil 44 being removed from thecircuit, coil 55 once more attracts the armature 33 and the operation isrepeated. The diminution of the electro-motive-force, by admission ofcoil 41 in the field magnet circuit and short circuiting' thereofthrough the operation of the regulating magnet described, produces veryactive and positive variation of the current supplied to the fieldmagnet windings. By this means the circuit is never broken in the fieldmagnet windings and therefore there is no discharge at the contactsbetween the armature 33 and the screw 36, but the resistance of thecircuit, through the field magnet windings-27 is increased, from aboutthree ohms, to somethinglike thirty ohms, thereby causing violentcurrent undulations to pass through the field magnet windings, andcorresponding magnetic impulses are engendered in the field cores ofboth magnets. Thus it will be seen that the circuits remain closedbetween the contacts 33 ahd 36 until the speed of the dynamo, and itsconsequent electromotive-force, rises above the critical point. Thenthecoil 55 attracts its armature 33 opening the circuit between contacts33 and 36, thereby admitting the rheostat 45 in circuit with the coil 44of the regulating magnet, which is in series circuit with the fieldwindings, and in parallel circuit with coil 41 thereby reducing thecurrent jcirculating through the field magnet winding and consequentlyits magnetizing power.

The higher the speed of the. dynamo, above the critical, the greaterwill be the tendency, and as a matter of fact the greater will be theactual disturbance produced in the magnetic field and the armature tooppose further rise of electro-motive force.

The electricalimpulses, superinduced by the opening of the contacts 33and 36 and the current surging through the field coils- 27, set upcounteracting self-induction or impedance effects in the field coils,which thereby reduce the current below that which would otherwise flowthrough the said coils.

The increase in the value of the current, due to the increase inelecti'o-mr)tiveforce, reacts upon the armature, and also contributestoward the reduction of rise of the electromotiveforce due to theincreased speed of the armature. Therapid changes of the magneticintensity of the field magnet, cffected by the electric impulsesproduced by the regulating magnet, produces hysteresis in the ironportion of the field magnets and this effect produces F aucault currentsin the magnetic mass, thereby inducing a' magnetic field reaction by thearmature, and eddy currents in the inductor itself, all of which effectstend to reduce the electro-motive-force impressed upon the brushterminals c'f the dynamo armature to such an extent as to maintainsubstantially constant the electro-motive-force of the armature, independently of the speed variations, above the certain predeterminedcritical point. These efi'ects are obviously intensified when the speedof the armature is increased above that at which it is adjusted tooperate.

Now, referring to the operation of the automatic switch or cut-out 17,it will be observed, that the coil 58, is in shunt across the wires 4and 5, including the coarse winding, or the coil 18. When theelectromotive-force of the dynamo is of the desired value, at which itis to be maintained, the current, that passes through the coils 58, issufficient to attract the armature 19, against the resilient action ofthe spring 22, so that the armature 19 makes contact with the screw 24,thereby completing the main circuit from the wire 4, through the'coil18, thus reinforcing the magnetic etlect produced by the coil 58, andholding the armature 19, in more firm contact with the screw 24. If theelectro-motive-force of the armature of the dynamo dominates that of thebattery 8, then the current will pass from the wire 4 through the coil18, and through the armature 19 by wire 25, to the wire 7; a portion ofthe current then passing to the battery 8 to charge it, to an extent inaccordance with the difference of their electro-motive-forces, and theother portion passing through the main 9, and the translating devices,bridged therebetween to the main 5. When the electro-mot-ive-force ofthe dynamo falls below the predetermined electro-motiveforce at which itis to be maintained, then current from the battery 8 will pass throughthe coil 18, in the opposite direction, overcoming the magnetic effectof the coil, 58; denergizing the core 21, and the armature 19 will beretracted by the spring 22, and break contact with the screw 24, therebydisconnecting the dynamo from the circuit, but leaving the'battery incircuit with the translating devices for which it may supply currentquite independently of the dynamo, and thus removing the dynamo from thedanger of being burned out by the current that would otherwise passthrough the armature of the dynamo. This being of relatively lowresistance, when not under speed, a large current would have the effectof overburdening the wires of the armature and thereby destroy it.

In a system, in substantial accordance with that of the diagram and theforegoing explanation, wherein the dynamo generated anelectro-motive-force of 7% volts and the battery had anelectro-motive-force of about 7 volts, the armature of the dynamo wouldrun at varying speeds to an extent more than equal double the criticalspeed, at which the normal voltage was generated, and the regulatoroperated in every way in the manner heretofore described, to maintainconstant electro-motive-force under such greatly varying speeds.

WVhatever may be the contributing causes to produce the resultsdescribed, whether hysteresis; armature reaction; magnetic variation, orcounter electro-motive-force, due to the undulations of current in thefield magnet; the fact remains that the results are produced, and I havegiven herein the causes which, in my opinion, have contributed to theresults pointed out, but I do not desire to be understood asspecifically stating that all of these effects are produced, or that anyone of them contribute to a greater extent than another. I have given,only my opinion, and I- am aware that considerable variation may be madefrom the exemplification which I have heretofore disclosed withoutdeparting from the spirit of the invention and within the scope of theappended claims.

What I claim is:

1. The combination'vvith a dynamo electric machine having main wires anda field circuit, of a rheostat, of resistance substantially greater thanthe field windings of said dynamo; a short circuiting device, for saidrheostat; two differentially Wound coils for controlling saidshort-circuiting device; and a second rheostat, in series with one ofsaid coils and of resistance substantially other of said coils bridgingsaid'main terminals of the dynamo, and circuit connections providing aplurality of parallels in series with said field circuit winding, onesaid parallel including the first mentioned rheostat, another includingsaid short-circuiting device, and another including the differentiallywound coil and the second rheostat in series.

2. The combination with a dynamo electric machine having main terminalsand a field circuit winding, of a rheostat, of resistance approximatelyten times that of the field winding of said dynamo; a short-circuitingdevice; a controlling and differentially wound coil for controlling saidshortcircuiting device, and a second rheostat, of resistanceapproximately ten times the first mentioned rheostat, one of saiddifferentially wound coils bridging the dynamo terminals, and shortcircuiting connections, providing a plurality of parallels in serieswith said field winding circuit, one of said parallels including thefirst mentioned rheostat; one said parallel including saidshort-circuiting device, and one said parallel including thedifferentially wound coil and the second mentioned rheostat, in series.

In testimony, whereof I hereunto set my hand iii the presence of twowitnesses.

, N. E. SNYDER, E. V. MARTIN.

greater than the first mentioned rheostat, the

